With 4 million dial-up subscribers and 1 million broadband users, EarthLink knows that the slower form of Internet access service will be around for years.

Given that, it is doing what it can to keep those narrowband users satisfied, so they'll stay with the Atlanta-based Internet service provider when they're ready to upgrade to high-speed access.

To that end, EarthLink has extended its contract with wholesale network services provider Level 3 Communications through mid-2005. Financial terms were not disclosed.

EarthLink began using Level 3's softswitch-based managed modem services more than four years ago and currently uses the service in hundreds of U.S. cities. In addition, Level 3 supplies EarthLink with private line, Internet protocol transit and co-location services that help support its growing broadband business.

Level 3 has proven its reliability, an EarthLink spokeswoman said. In addition to the Broomfield, Colo., provider, EarthLink also contracts with Qwest , MCI's UUNet division and Sprint , she added.

ISPs use several providers for two reasons: to help negotiate the best deals and to insure network performance if one of their suppliers suffers an outage.

In a related development for Level 3, the company launched a new technical field support service for its co-location and dark fiber customers in the United States and Europe. Called (3)Tech, the offering covers customers' network maintenance. The services are provided by Level 3 technicians 24 hours a day across the Level 3 network footprint.

The Corporation for Education Network Initiatives in California (CONIC) is among the first customers of the (3)Tech service. A Level 3 spokesman did not immediately respond to a request for comment.